two columns on mobile instead of stacking issue

Hi all. I'm trying to get my gallery grid block to show two columns on mobile instead of stacking. I've used the CSS below to accomplish it but the grid is not aligning correctly on mobile wit the third item being bumped and white space in its place- screenshot attached (On tablet and desktop view it's also two columns wide but doesn't have the same issue). The page is here: https://ugly.wtf/new-page-1

I'm able to correct the problem using white-space: nowrap; but then my text obviously doesn't wrap as needed. 

Any help would be much appreciated. I'm very inexperienced with CSS. 

Thanks in advance,

<style>
@media only screen and (max-width: 640px)
{.sqs-block-summary-v2 .summary-item {
  	clear: none !important;
    width: calc(100%/2)!important;
  	padding: 2px !important;
  }
  }
</style>